圆巷开挖围岩偏应力应变能生成的分析解与图解

巷道开挖在围岩中产生偏应力,围岩应力是原岩应力与偏应力的叠加,偏应力或偏应力能控制岩体破坏。在假设静水压力和体积应变等于零条件下,利用文献1]在弹性、非线性硬化和软化光滑连接的本构模型导得的圆巷围岩弹性、硬化和软化区光滑连接的应力分布表达式,用重积分计算了圆巷围岩弹性、硬化和软化区中的偏应力应变能U d,证明了Ud可以简捷地用地应力关于巷壁位移做一次积分再乘以巷壁周长得到。由此,可通过地应力–巷壁位移关系曲线及其所围面积的几何形式表示围岩偏应力能随巷壁位移变化的情况,此研究结果可以深化由于巷道开挖围岩的力学响应及挖成后巷道围岩工况规律的认识。

Analysis and illustration on deviatoric stress strain energy generation of surrounding rock in circuar tunnel excavation

The stress in surrounding rock is the superposition of stress in virgin rock mass and deviatoric stress happened in circuar tunnel excavation.The breakage of rock mass by was dominates by the deviatoric stress or its strain energy.On condition that hydrostatic pressure and volumetric strain of rock mass equalled to zero,by using the stress distribution expressions of surrounding rock that its elastic,nonlinear hardening and nonlinear softening zones were linked glossily based on the constitutive model of Reference1],and using multiple integral,the strain energy of deviatoric stress,U d,was calculated in the elastic,hardened and softened zones of surrounding rock.It was proved that U d could be deduced concisely by integrating geo-stress with respect to displacement of tunnel wall,and multiplying by the perimeter of tunnel wall.Thereby,the variation of the deviatoric stress energy in surrounding rock in response to the displacement of tunnel wall could be expressed by the geometric form of the relation between geo-stress and displacement of tunnel wall as well as the area enclosed by them.The obtained results could deepen the understanding of mechanical response of surrounding rock due to the excavation and operation of tunnels.